1. Field of the Invention
The present invention relates generally to seals, and more particularly to sliding seals of the type wherein sliding motion between the seal and another member occurs. The sliding seal of this invention comprises a pile seal member secured to a channel-shaped gripping element. A protective arm-guard extends from one of the pile seal members or gripping elements to prevent penetration of the pile by foreign material such as stones or the like.
2. Description of the Prior Art
U.S. Pat. No. 3,175,256 relates to a weather-seal having a base strip and two longitudinally extending parallel spaced rows of pile attached to the base strip. An impervious fin of thermoplastic material is secured on edge to the base strip in the space between the rows of pile.
U.S. Pat. No. 3,198,689 discloses a weatherseal mountable on a flange around a door or window opening in a motor vehicle body to prevent water and air leakage into the body. The weatherseal comprises a channel member having gripping means by which the seal is mounted on the flange. The gripping means comprises gripping ribs extending longitudinally along the inside surface of the channel member, projecting toward each other from the opposite side walls thereof. Although only one rib is shown on each side wall, it is known in the art to provide more than one, if desired.
U.S. Pat. No. 4,114,320 discloses a door seal having a channel-shaped gripping element, and a tubular seal secured to a portion of the outer surface of the channel-shaped element.
It is further known in the prior art to provide a longitudinally extending deformable seal such as a rubber gasket or the like for sealing a swingable refrigerator door. The seal is secured to the door frame by any suitable means, and is sealingly engaged by a surface of the door when it is swung to its closed position.
Although the deformable seal provides an adequate seal for swingable doors, it is unsatisfactory for roll-up type overhead doors in refrigerated trucks, trailers or box cars. One of the problems is that the sliding motion between the deformed or compressed seal and the door surface results in abrasion which is potentially damaging to the seal and door. Seal damage can result in air leakage. This, in turn, can increase the work load on the refrigerator system and its cost of operation. In addition, possible damage to the refrigerated perishable product can result, particularly if the refrigeration system breaks down.
Leaf seals are also known in the art for sealing the space between the surface of a roll-up door and the door frame. One problem with this type of seal, in addition to the abrasion problem noted above, is that the unevenness or irregularities in the roll-up door surface prevents securing a good seal. Another problem is that the leaf seal is oriented to offer more resistance to inward air flow than outward resulting in possible loss of refrigerated air outwardly through the seal.